title: The spin glass delafossite CuFe(0.5)V(0.5)O(2): a dipolar glass?
abstract: The ferroelectric and spin glass properties of CuFe(0.5)V(0.5)O(2) have been studied. Magnetization, ac magnetic susceptibility and specific heat measurements reveal a spin glass behavior (T(f) = 20.5 K) for this delafossite. In CuFeO(2), substitution of trivalent diamagnetic cations for Fe(3 + ) is known to change the antiferromagnetic state and induce ferroelectricity. But partial occupation of the Fe(3 + ) site by V(3 + ) is responsible for disordered magnetism in CuFe(0.5)V(0.5)O(2). The dielectric permittivity shows a frequency dependence reminiscent of relaxor ferroelectrics in which different cations occupy the same crystallographic site. Polarization measurements show the existence of a ferroelectric state below T(f) with P(5 K)≈1.3 µC m( - 2). These results point towards a relaxor-type ferroelectricity originating from a disordered array of magnetic cations. A clear coupling between electronic charges and spins is evidenced by the magnetodielectric effect.
authors.affiliation: Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex, France.
authors.forename: Kiran
authors.initials: K
authors.lastname: Singh
authors.forename: Antoine
authors.initials: A
authors.lastname: Maignan
authors.forename: Charles
authors.initials: C
authors.lastname: Simon
authors.forename: Vincent
authors.initials: V
authors.lastname: Hardy
authors.forename: Elise
authors.initials: E
authors.lastname: Pachoud
authors.forename: Christine
authors.initials: C
authors.lastname: Martin